Thursday, March 5, 1998 Published at 17:58 GMTSci/TechWhat we can make of Moon waterIn the next millennium, people may be living on the Moon

Nasa scientists announce that the Lunar Prospector mission has found ice on the Moon. The BBC's Science Correspondent, Dr David Whitehouse, explains how water on the Moon could serve those of us on Earth.

Finding ice on the Moon is a major discovery that could set the course of the human exploration of space for the next 20 years.

It would make the Moon a much more attractive place to build a manned base.

Before Lunar ice was confirmed many scientists wanted to plan to land people on Mars which, although a larger and more interesting body that the Moon, is much further away. Missions to Mars would cost hundreds of times that of missions to the Moon.

To build the first Moonbase, astronauts will need the ice and some ingenuity. There in the lunar rocks is everything required for supporting life as well as many profitable industries.

Oxygen makes up half the weight of lunar rocks and is straightforward to extract, requiring only energy that may come from small nuclear power plants or from solar power.

The only thing that the Moon lacks is hydrogen. Ice near the lunar poles would provide it. It could be used for drinking, for irrigation and for rocket fuel.

Lunar ice could mean cheaper rocket fuel

The oxygen and hydrogen extracted from Lunar ice could be used as a much more energy-efficient way of sending space stations and satellites into orbit around the Earth.

Liquid hydrogen and liquid oxygen are the fuel of the Space Shuttle.

Ninety-nine per cent of the energy used to get rocket fuel into space is spent launching it the first 150 miles from the surface of the Earth into Earth orbit.

Because the Moon has weaker gravity it would require less energy to send rocket fuel to Earth orbit from the Moon than it would to send it up from the Earth's surface.

Exploring the dark side of the moon

The Lunar Prospector spacecraft is a small and relatively cheap craft that was launched with one main goal - to find out if there is ice on the moon.

During the Apollo Moon landings astronauts showed us that the moon is drier than any place on Earth: not a hint of moisture was found.

Nasa simulation of the Lunar Prospector leaving Earth in January

But in 1994, a military satellite called Clementine suggested that there might be ice nestling in dark regions near the lunar poles.

The area around South Pole Crater is one of the most remarkable places in the solar system.

On its western limb is the so-called "Peak of Eternal Light" a region of the moon that is in constant sunlight.

Not far away, in the depth of a cavernous crater, is a place where sunlight never reaches. It is in cracks and fissures in such eternally dark, and cold, regions where it is thought ice could exist.

Since Lunar Prospector entered orbit and began is survey of the Moon, scientists have been delighted with the data it has been sending back.

A month ago the BBC broke the news that many scientists believed that the signature of ice had been seen. Now those scientists and the American space agency Nasa have confirmed that.